Influence of Film Roughness on the Soft Magnetic Properties of Fe/Ni Multilayers

The influence of surface/interface roughness on the magnetic properties of Fe/Ni multilayers is investigated. Two methods are employed to tune the film roughness: one varies the substrate temperature, and the other pre-deposits a Ag underlayer on the MgO substrate. For films with higher roughness, a marked rise in coercivity is observed. Three factors are discussed to be mainly responsible for the coercivity rise, involving the formation of pinholes, the reduction of exchange coupling between Fe and Ni layers, and Fe-Ni alloying at interfaces.